if you will not be working from 62 to 70 and living off your own savings then the equation shifts a lot . if you will be spending down invested assets those assets are done compounding forever . also , like in our case my wife gets a spousal adder to hers since she is collecting early but until i file she gets no additional kicker of 2500.00 a year . . then of course we have the checks you didn't collect . ONE OTHER THING IS UNTIL YOU COLLECT THE HOLD HARMLESS MEDICARE LAW DOES NOT PROTECT YOU . for 2016 there is a huge jump in medicare of more than 50 bucks a month coming . if you are collecting you can not be raised more than the cola adjustment . since there is none there will be no increase if collecting . if not collecting you get the full increase . based on a balanced fund and all of the above , break even is not until 22-23 years out ,. that is a far cry from just figuring lost checks . that is a very long time just to reach ground zero . you need to live to 90 or a spouse does to make it worth delaying and getting a big enough difference so taking the risk of not reaching break even is worth it as you are betting against the house when you bet on longevity to that age ,. there still are reasons for waiting like survivor benefits and reduced dependency on markets down the road , but the point is it is more than looking at 8 years of checks difference . .